JPS628936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for bonding chips mounted on a thick film substrate.

From the structural standpoint of attaching the chip, there are two ways to bond the chip: (a) back bonding (face-up bonding) where the chip is attached to the substrate with the active surface (electrode bonding surface) facing up; (b) back bonding (face-up bonding) where the chip is attached with the active surface facing down (substrate ), and (c) the decal bonding method, which includes the above (a) and (b) in the bonding process. Conventionally, when attaching a chip with solderable electrodes on both sides to a board, a special contact (lead electrode) was used to connect the upper electrode, and a special decal was used to simultaneously solder the electrodes on both sides of the chip using a thermocompression method. A bonding method is used. In this case, since contacts are used, high precision is required for alignment with the chip electrodes, and a jig for positioning the chip and contacts is required. Furthermore, when mounting together with other elements on a thick film substrate, the thick film process becomes complicated.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art by bonding the conductor electrode on the thick film substrate and the upper electrode of the chip with solder.
The purpose is to eliminate the need for chips, contact positioning jigs, and special contacts that have been used in the past, as well as the need for a special thick film process for solder bonding.

When a chip with solderable electrodes on both sides is attached to a thick film substrate, the present invention eliminates the need for special contacts and jigs that have been used in the past, and further simplifies the thick film process. The conductor electrodes on the film substrate are bonded by bridging with solder paste during reflow of the entire thick film substrate.

Hereinafter, embodiments of the present invention will be explained with reference to the figures.
FIG. 1 shows a triax chip 5 mounted on a thick film substrate.
is mounted on the alumina substrate 2, first
An Ag-Pd conductor electrode 1 is printed, a glass insulating layer 3 is printed on it, a solder paste 4 is printed on it, and finally the upper electrodes 6-1, 6- of the tri-chip 5 are formed. 2 to alumina substrate 2
It is mounted facing the opposite side.

FIG. 2 shows an example in which the thick film substrate on which the triax chip 5 shown in FIG. upper electrode 6 of the triax chip 5
-1, 6-2 and Ag--Pd conductor electrode 1 are soldered together with bridged solder 8-1, 8-2.

Figures 3a and 3b show an Ag-Pd conductor electrode 1 on an alumina substrate 2, and a solder bridge between the upper electrodes 6-1, 6-2 of the triax chip 5 in Figure 2 and the Ag-Pd conductor electrode 1. The pattern shape printed as it occurs is shown. Figures 4a and 4b show a pattern in which a glass insulating layer 3 was printed on the alumina substrate 2 up to the step where the Ag-Pd conductor electrodes 1 were printed to prevent short circuits between the Ag-Pd conductor electrodes 1. Show shape. 5a and 5b show that the upper electrodes 6-1, 6-2 of the triax chip 5 and the Ag
- Solder bridging occurs between Pd conductor electrode 1,
It also shows the pattern shape printed to ensure the necessary amount of solder. 6a, b, and c are the upper electrodes 6-1, 6-2 of the triax chip 5.
and shows the shape of the lower electrode 7.

As described above, the present invention has the following significant effects.

() No special contacts are required.

In the solder joint with the upper electrode of the chip,
Conventionally, special contacts have been used, but the present invention has made these unnecessary.

() No positioning jig for chips or special contacts is required. Conventionally, when a special contact is soldered to the upper electrode of a chip, a highly accurate positioning jig has been used, but the present invention has made this unnecessary.

() No special thick film process is required for solder joints. Conventionally, when a chip is attached to a thick film substrate together with other elements, a special process is required for soldering and the thick film process becomes complicated. The chip can be attached at the same time as the device, eliminating the need for a special thick-film process for soldering the chip.

From the above, the present invention greatly improves work efficiency when attaching chips to thick film substrates, and facilitates automation of the mounting process.
This leads to a significant cost reduction as a thick film substrate.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a thick film substrate on which a triax chip is mounted before reflow, FIG. 2 is a cross-sectional view of a thick film substrate on which a triax chip is mounted after reflow, and FIG. Figure 3b is a plan view showing the shape of the Ag-Pd conductor electrode pattern on the substrate.
4a is a plan view showing the pattern shape of the glass insulating layer on the thick film substrate; FIG. 4b is a sectional view taken along the line B-B in FIG. 4a; Figure 5a
is a plan view showing the pattern shape of the solder paste on the thick film substrate, FIG. 5b is a sectional view taken along the line C-C of FIG. 5a, and FIGS. A plan view showing the electrode, Fig. 6b is similar to Fig. 6a.
It is a sectional view taken along the line DD. DESCRIPTION OF SYMBOLS 1...Ag-Pd conductor electrode, 5...Triac chip, 6...Upper electrode, 7...Lower electrode, 8-
1,8-2... Brisked solder.

Claims (1)

[Claims] 1 A bonding method in which a chip having solderable electrodes on both upper and lower surfaces is attached to a plurality of conductor electrodes printed on a substrate, in which the lower electrode of the chip and the conductor electrode of the substrate are bonded facing each other, A method for soldering chips, characterized in that the upper electrode of the chip and the conductor electrode of the substrate are joined by bridging with solder.